A study of how the lambda phage particle functions in the injection process is proposed as a model system for protein-protein and protein-DNA interaction. The binding of the phage tail to its receptor in the bacterial membrane and the subsequent triggering of DNA release from the phage is a process involving coordinated interactions among membrane components, phage proteins and DNA. It is proposed to purify certain of these components and study their interaction and the effects of mutational variations in the primary structure of the phage tail fiber and the bacterial receptor on their interaction. The binding of di- and polyamines stabilizes certain DNA structures. The effect of such binding on the affinity for ethidium intercalation will be determined. In another experimental system, mouse chromosomes will be fractionated to obtain chromosome 17 for a study of structure, function and the possible isolation of specific gene regions. BIBLIOGRAPHIC REFERENCES: Mackay, D. and Bode, V. C. (1976). Binding to Isolated Phage Receptors and lambda DNA Release in vitro. Virology 72, 167-181. Harrison, D. P. and Bode, V. C. (1977). The Lambda Head-Tail Joining Reaction: II. A Putrescine Requirement for the Efficient Joining of Lambda Heads and Tails. Virology, in press.